Yarn processing system

ABSTRACT

A yarn processing system which includes a yarn feeding device and an accessory device associated with the yarn feeding device. The accessory device has a device which is driven using a signal representing the rotational speed of a component of the yarn feeding device. The signal is generated by an electronic sensor galvanically separated from the control system and the drive mechanism of the yarn feeding device. The sensor also is structurally independent from the yarn feeding device. The sensor is located at or close to the yarn feeding device at a mounting location where a part of a rotating magnetic field is detected by the sensor at the mounting location. The part of the magnetic field originating from inside of the yarn feeding device is not used for the operation of the yarn feeding device at the mounting location of the sensor.

FIELD OF THE INVENTION

The present invention relates to a yarn processing system, as well as toan electronic sensor for a yarn feeding device.

BACKGROUND OF THE INVENTION

In a yarn processing system as known from EP 06 19 262 A and DE 44 14870A, respectively, the accessory device processing the yarn is a yarnoiler mounted with a carrier means to the inlet side end wall of thehousing of the yarn feeding device. The yarn oiler includes a controlunit for an electric drive motor driving a treatment element by which animpregnation substance like wax or oil is applied onto the yarn. Therotational speed of the treatment element is related to the rotationalspeed of a component in the yarn feeding device, and as such indirectlyto the yarn speed. Said component is conveying the yarn within the yarnfeeding device and is driven by an electric motor and in a controlledfashion. The yarn feeding device is prepared with its control system andits housing design for a functional and structural controlled co-actionwith the yarn oiler. A cable, preferably with a detachable connector,extends from the control system of the yarn feeding device through andout of the housing of the yarn feeding device to the control unit of theyarn oiler and is transmitting a signal by galvanic conduction, whichsignal represents the rotational speed in the yarn feeding device. Thisaccordingly necessitates a structural preparation of the yarn feedingdevice for the co-action with the yarn oiler and excludes the usage perse of the yarn oiler with other yarn feeding devices having no suchcorresponding preparation. The prerequisites are similar for the othersuch accessory devices like controlled yarn brakes, slip conveyors orrotational drives for storage bobbins from which the yarn feeding deviceis pulling off the yarn, because all of said accessory devices also needsaid rotation speed signal for the co-action with the yarn feedingdevice. In case that the yarn feeding device is used without theaccessory device, the costly preparation of its control system and itshousing is superfluous. In addition, the provided galvanic connectionfor the speed signal transmission might undesirably influence thecontrol of the yarn feeding device in case of a disturbance at the sideof the accessory device or along the signal transmission path.

It is a task of the invention to provide a yarn processing system of thekind as disclosed above as well as an electronic sensor which are ableto avoid a preparation of the yarn feeding device in terms of itscontrol system and/or its design, in view of a co-action with any kindof such speed depending controlled driven accessory device, and whichfurthermore allow one to easily use any speed depending driven accessorydevice at different types of yarn feeding devices, and wherein thedanger of a disturbing influence of the accessory device with respect tothe control system of the yarn feeding device is avoided.

Since the sensor according to the invention is galvanically separatedand independent from the yarn feeding device, it can be used practicallyfor any type of yarn feeding device, even if the yarn feeding device asused has no constructional preparation or adaptation of its controlsystem for a transmission of a speed signal to the exterior. By this theproduction costs of the yarn feeding device can be reduced. Any type ofaccessory device of the kind as mentioned above can be combined laterwith yarn feeding devices already in use. Surprisingly simple, at leastan outwardly leaking part of a rotating magnetic field can be detectedfrom the exterior of a yarn feeding device which has an interiorcomponent which is rotatably driven by an electric motor in a controlledfashion. Said leaking part of the rotating magnetic field is availableat the mounting location of the sensor but is not used at this locationfor the function of the yarn feeding device. It is only necessary toselect the mounting location of the sensor such that the sensor is ableto reliably detect the rotation of the magnetic field. On the basis ofsaid leaking part of the magnetic field, the sensor generates a signalrepresenting the rotational speed of the component within the yarnfeeding device. Normally, the housings of yarn feeding devices are notsufficient to shield or suppress the leakage of a part of the magneticfield, which leaking part suffices for detection and generation of thespeed signal. Sensors detecting the leakage or wasted part of themagnetic field allow expansion of the range of applications for yarnfeeding devices and for accessory devices being driven in dependencefrom the rotational speed of the yarn feeding devices, since thanks tothe sensor, such accessory devices can even be applied on yarn feedingdevices which per se are not prepared for a speed depending co-actionwith any accessory devices.

The signal is transmitted to the accessory device from the signal exitport of the sensor, preferably to the control unit of the accessorydevice. The signal then is used in the accessory device depending on thecontrol routine of the accessory device. In any case it is assured thatthe speed signal is available when necessary without interfering withthe control system or the drive means of the yarn feeding device by aprefabricated and/or disturbance-sensitive galvanic connection. Providedthat the sensor is equipped with a signal cable and a detachableconnector, the sensor can be combined with any type of accessory deviceneeding said speed signal. Accessory devices may be used with the sensorwhich already are prepared for a galvanic connection with the controlsystem or the drive means of the yarn feeding device.

The sensor can include its own power supply and is independent from theyarn feeding device, and optionally, also from the accessory device.

The sensor can be supplied with operational power either from theaccessory device or independently of the accessory device from a powersupply box of the yarn feeding device. Such box is usually equipped withspare connection ports or connection ports thereon can be provided withminimum effort. Furthermore, the sensor may be connected to a completelyindependent power supply or may be provided with a battery inside suchthat the sensor remains completely independent from any other powersource.

The sensor can be used at least to assist in the control of a yarnimpregnation device, e.g., a yarn oiler, which is provided along theyarn path in order to apply an impregnation substance such as oil or waxon the yarn. This impregnation is important for certain yarn qualitiesin view of a proper processing of the yarn.

The accessory device in one embodiment is a slip conveyor having atleast one friction roll driven in dependence from the rotational speedin the yarn feeding device or from the yarn speed. Said slip conveyoreither assists in withdrawing the yarn at a withdrawal side from theyarn feeding device or in conveying the yarn at the inlet side towardsthe yarn feeding device.

The accessory device in another embodiment is a controlled yarn brake,the braking effect of which is variable depending upon the yarn speed.Said controlled yarn brake may be provided at the inlet side and/or atthe withdrawal side of the yarn feeding device.

The accessory device using the speed signal of the sensor is arotational drive of a storage bobbin carrying the yarn for the yarnfeeding device. The purpose of said rotational drive is to reduce oreliminate the twist or drill of the yarn normally resulting when pullingoff yarn from a stationary storage bobbin. This can be important forhigh fabric quality when weaving Lurex or band yarns.

The sensor is mounted at its mounting location by the carrier means ofthe yarn impregnation device, preferably at or close to the inlet sidehousing end wall of the yarn feeding device. At this location,particularly in the area of the inlet eyelet of the yarn feeding device,e.g. the rotation of the magnetic field of the drive motor is easilydetectable by the sensor. The sensor may be integrated per se into thecarrier means. Alternatively, the sensor may be designed with its ownfixing means, or the carrier means may be provided with a fixing meansenabling simple positioning of the sensor.

The speed signal generated in the sensor is transmitted to the controlunit of the electric motor of the treatment element of the yarnimpregnation device. If the signal exit port of the sensor ispermanently connected with the control unit, the sensor so to speak isan integrated part of a structural unit consisting of the yarnimpregnation device, the carrier means and the sensor. In case that thesignal exit port is releasably connected to the control unit, the sensoralso may be selectively used with other types of accessory devices. Itthen is even possible to connect the yarn impregnation device in aconventional galvanic manner without the sensor to the control system ofa yarn feeding device accordingly prepared for the galvanic co-actionwith the yarn impregnation device. One type of an accessory device maybe selectively combined with different yarn feeding devices.

A receiving socket for the sensor is formed at the housing of the yarnfeeding device, e.g., an insertion opening, a threaded bore or a hang-inhole. Said receiving socket can readily be formed with tools availableat the working location of the yarn processing systems, e.g. in aweaving mill. It is also possible to form a receiving socket like aninsertion opening, a bayonet socket, a screw-in socket or the like inthe yarn feeding device housing during manufacturing of the yarn feedingdevice, however, without using any galvanic connection to the controlsystem or the drive means of the yarn feeding device.

The accessory device is located separately and remotely from said yarnfeeding device, while the sensor is located at or close to the yarnfeeding device. Signal transmission takes place via a cable. This allowspositioning of the accessory device arbitrarily at a location where itoptimally fulfills its purpose.

The part of the magnetic field used for the speed detection is a leakingout part of a driving, controlling or monitoring magnetic field of thedrive motor, i.e., of an electric motor of the yarn feeding device. Therotation of the magnetic field is representing the momentary rotationalspeed of all components in the yarn feeding device driven by saidelectric motor, or the rotational speed of the motor itself, or even themomentary yarn speed, respectively.

The sensor for deriving the speed signal detects the rotation of a partof a magnetic field, which part is not used for the function of the yarnfeeding device at the mounting location of the sensor. Said magneticfield originates from a permanent magnet belonging to a rotationdetector which is integrated into the yarn feeding device.Conventionally, the winding element is defined by an outwardlyprotruding winding tube and/or a winding disk on the drive shaft and ismade of non-magnetic material. The rotation detector integrated into theyarn feeding device (e.g. U.S. Pat. No. 4,715,411) consists of thepermanent magnet provided at the winding element, and of a stationarilypositioned detecting element like a Hall element. The rotationalmovement of the magnetic field generated by the permanent magnet duringoperation of the yarn feeding device is detectable by the sensor evenwhen it is galvanically separated from the control system and the drivemeans of the yarn feeding device. For said purpose the sensor ought tobe situated close to said winding element at the stationary housing ofthe yarn feeding device.

The sensor is provided with a probe-shaped housing for the pick-up headapt to detect rotating magnetic fields and/or magnetic field variationsof rotating magnetic fields without galvanic connection. The housing ofthe sensor is to be positioned where at least a part of a magnetic fieldis leaking outwardly to the pick-up head, said part not being used forthe function of the yarn feeding device at the mounting location of thesensor. It is possible to provide a fixation means at the sensor. Inorder to gain a forceful and clear speed signal and to achieve acompletely independent operation of the sensor, amplification andevaluation circuitry might be useful if received in the sensor housing.

The sensor easily may be glued to the housing at the mounting location.

The sensor can also be mounted with a fixing band at the housing of theyarn feeding device.

At least one of the existing protrusions or cooling fins of the housingof the yarn feeding device is used to mount the sensor at its mountinglocation by means of a clamp engaging at said protrusion or cooling fin,respectively.

The speed signal generated by the sensor without a galvanic connectionwith the control system or the drive means of the yarn feeding device isused in the accessory device to control the movement of a part thereofdepending upon the rotational speed in the yarn feeding device. It ispossible to control said part permanently or only in predeterminedoperational phases according to said rotational speed. The part may thenbe controlled in direct or indirect proportion to the rotational speed.In a yarn impregnation device with a rotating treatment element, thespeed signal is used to vary the rotational speed of the treatmentelement. In a controlled yarn brake said speed signal is used to varythe braking or tensioning effect on the yarn by means of at least onemovable braking element. In a drive for a storage bobbin, said speedsignal is used to rotate said bobbin according to the rotational speedin the yarn feeding device such that the yarn leaving the bobbinreceives only a reduced drill or no drill or twist at all. In a slipconveyor, a slip element is driven accordingly to adjust the slip in theyarn conveying direction corresponding to the momentary yarn speed.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be explained with reference to thedrawings, in which:

FIG. 1 is a schematic side view of a yarn processing system; and

FIG. 2 is an enlarged side view of a sensor detecting the rotationalspeed in a yarn feeding device or the linear speed of the yarn enteringthe yarn feeding device.

DETAILED DESCRIPTION

A yarn processing system T in FIG. 1 comprises as a main component ayarn feeding device F, namely and as shown, a weft yarn storing andfeeding device for a weaving machine. Instead of a weft yarn storing andfeeding device, said yarn processing system T could include a yarnstoring and feeding device for a knitting machine, e.g. with a rotatingstorage drum (not shown). In the path of a yarn Y processed by the yarnfeeding device F for downstream consumption, at least one accessorydevice Z, Z1, Z2, Z3 is provided co-acting with the yarn feeding deviceF such that the accessory device is mechanically acting upon the yarn Ydepending upon the linear yarn speed or the rotational speed of at leastone component rotating inside the yarn feeding device F.

The accessory device Z may, e.g. be a yarn impregnation device 9, i.e. aso-called yarn oiler, applying a substance (oil or wax) onto the yarn Yin order to facilitate its further processing in the yarn feeding deviceand/or in the textile machine (weaving or knitting machine) consumingsaid yarn. Accessory device Z in FIG. 1 is mounted to a housing 1 of theyarn feeding device F. It is, however, possible to instead position therespective accessory device, i.e. even the yarn impregnation device Z,elsewhere along the yarn path and separated or remote from the yarnfeeding device F as shown in dotted lines for e.g. accessory device Z2,between the yarn feeding device F and a yarn storage bobbin 15.Alternatively or additively to the yarn impregnation device 9, saidaccessory device Z2 could be a controlled yarn brake or a controlledyarn tensioner located between the storage bobbin 15 and the yarnfeeding device. Accessory device Z mounted to housing 1 instead of saidyarn impregnation device 9 may be a controlled yarn input brake.Accessory device Z3 shown in dotted lines could be a controlled yarnbrake at the exit or output side of the yarn feeding device. Also oneaccessory device (e.g. Z, Z2 or Z3) could be a controlled slip conveyorwithdrawing the yarn at the output side of the yarn feeding device F orconveying the yarn to the inlet side with slip by means of at least onedriven friction roll. Accessory device Z1 shown in dotted lines atstorage bobbin 15 may be a rotation drive for the storage bobbin 15 todrive the latter with a variable rotational speed such that duringwithdrawal of the yarn Y from the storage bobbin 15 no or reduced twistoccurs. In brief, in the yarn processing system T of FIG. 1, only oneaccessory device or several accessory devices may be used.

The accessory device as used includes a movable part, the movement ofwhich at least temporarily must take into consideration the rotationalspeed in the yarn feeding device F or the linear speed of the yarn Y.For this reason, a speed signal generated by an exterior locatedelectronic sensor S is transmitted for control purposes to the accessorydevice. In the yarn processing system T, a common sensor S could be usedfor all respective accessory devices, or a number of sensors Scorresponding to the number of accessory devices may be provided.

Yarn feeding device F is receiving in housing 1 an electric motor Mdriving a drive shaft 2 of a winding element 4. Yarn feeding device Fhas a storage drum 3 for storing the yarn Y in windings from whichwindings the consuming textile machine (a weaving or a knitting machine)is withdrawing the yarn axially or tangentially. The electric motor M ofthe yarn feeding device F is connected to a control system C to whichsignals of a schematically indicated yarn sensor device 6 may be inputfor control purposes. Housing 1 may include a rotation detectorintegrated into the yarn feeding device F in signal transmittingconnection with control system C, as indicated. Said rotation detectorconsists of a permanent magnet 8 secured to the winding element 4, andof a stationary detecting element 7 associated and aligned with thepassage path of said permanent magnet 8. winding element 4 is a diskmade of non-magnetic material and rotates with drive shaft 2. Permanentmagnet 8 is fixed to said winding disk at an appropriate location. Yarnfeeding device F is supplied with operation and control power via acable 5 connected to a power supply box B, to which further yarnprocessing systems of the textile machine can be connected as well (notshown).

The yarn impregnation device 9, e.g. constituting said accessory deviceZ, comprises at least one treatment element 10 (e.g. an applicationroll) rotatably driven by an electric motor M1. Treatment element 10receives an impregnating substance, e.g. from a not shown wick, andtransfers said substance onto yarn Y while the latter is guided throughthe yarn impregnation device 9. An electronic control unit C1 isprovided in said yarn impregnation device 9 for electronic motor M1.Operation and control power for the yarn impregnation device 9 issupplied via a cable 11 either from its own power source or as shownfrom power supply box B.

The accessory device C or the yarn impregnation device 9, respectively,is fixed by a carrier means 12, e.g. by at least one holding bracket tohousing 1, either at the lower side of housing 1 or at an inlet side endwall of housing 1. In said inlet side end wall of housing 1,conventional fixation bores for accessory devices of different kinds arepre-formed. Sensor S is integrated into carrier means 12 such that itcontacts the housing end wall or is located adjacent to it, particularlyat a mounting location X. During rotation of at least a component K ofthe yarn feeding device F (e.g. of electric motor M), the sensor atmounting location X detects at least a part of a rotating magnetic fieldwhich leaks through housing 1. Sensor S is incorporated into carriermeans 12 either by its own fixation part 13 or by a fixation means G.Said rotating magnetic field may be the driving, the controlling or thesupervising magnetic field of the electric motor M, respectively.

The sensor S is an electronic sensor deriving a signal from the rotationof the magnetic field or the detected part of said magnetic fieldwithout having galvanic connection to the control system C or theelectric drive motor M of the yarn feeding device F. Said signal isrepresenting the rotational speed in the yarn feeding device F andindirectly the linear yarn speed as well, since the yarn Y is wound ontostorage drum 3 by the rotation of winding element 4.

In the embodiment shown, the sensor S is connected via a signaltransmitting and, optionally, a power supply cable 14 to a connectionport 20 of accessory device Z. Connection port 20 can comprise a plugsuch that the connection is releasable. Alternatively, sensor S can beconnected to its own power supply, e.g. to the power supply box B oreven to a completely separated power source. As an example, adash-dotted line indicates a connection between sensor S and powersupply box B. Instead, sensor S could be equipped with its own permanentpower source, e.g. a battery, in order to operate the sensor Scompletely independently. Since here accessory device Z already issupplied with power via a cable 11, it is suitable to supply sensor Salso directly with operational power from accessory device C, e.g. viacable 14. The respective accessory device Z, Z1, Z2 and Z3 receives thespeed signal on signal cable 14.

In FIG. 1 in dotted lines, another mounting location X1 for such asensor S is shown. Said location X1 is situated close to winding element4 such that sensor S positioned at X1 at housing 1 is detecting therotation of the magnetic field to generate the necessary speed signalwithout the galvanic connection to the control system C or to drivemotor M of the yarn feeding device F. Said leaking part at location X1of the magnetic field otherwise is not used for the operation of theyarn feeding device F.

Sensor S may—as explained—be positioned with its fixation means G at theselected mounting location X or X1. Alternatively, it is possible forthis purpose to form a receiving socket for sensor S in housing 1 of theyarn feeding device F, e.g. an insertion bore socket, a threaded bore ora hang-in opening. It is even possible to beforehand manufacture thehousing 1 of the yarn feeding device F with an insertion socket, athreaded socket, a bayonet socket or a hang-in opening for sensor S orfor the fixation means G of sensor S.

The electronic sensor S in FIG. 2 has a probe-shaped housing 16receiving a pick-up head A, e.g. in the region of a housing end portion17. Optionally, at housing end portion 17, an elastic layer 18 may beprovided thereby avoiding a direct hard contact between housing 16 andhousing 1 (FIG. 1). The fixation means G of sensor S in FIG. 2 here iscollar-like and is secured to housing 16, preferably in an axiallydisplaceable fashion, and comprises a fixation part 19 which might beequipped with different fixation points or fixation means in order toposition the sensor S at the intended mounting location X or X1 or atanother not shown mounting location. An amplifying circuitry D and aevaluation circuitry E can be integrated into housing 16. The speedsignal is output at signal exit port H of sensor S to be transmitted viacable 14.

As a fixation means G for sensor S, a plastic, rubber or foam materialbody on housing 16 could be used having a permanent adhesive coatingsuch that sensor S simply can be glued to housing 1. Alternatively,sensor S could be secured by means of a tensioning band extending aroundhousing 1 or around a part of housing 1 of the yarn feeding device F. Asa further alternative, a spring loaded clamp could constitute saidfixation means G. Said clamp could be secured to an existing protrusionor a cooling fin of housing 1. In case that no accessory device Z ismounted directly to housing 1, carrier means 12 or a similar carriermeans could be used to solely position sensor S at the intended mountinglocation X or X1.

Although a particular preferred embodiment of the invention has beendisclosed in detail for illustrative purposes, it will be recognizedthat variations or modifications of the disclosed apparatus, includingthe rearrangement of parts, lie within the scope of the presentinvention.

What is claimed is:
 1. A yarn processing system comprising a yarnfeeding device and at least one accessory device associated with saidyarn feeding device, said yarn feeding device including at least onecomponent driven in a controlled fashion by an electric motor, saidaccessory device having at least one movable part which is driventhrough use of a signal representing the rotational speed of saidcomponent of said yarn feeding device, said signal being generated in anelectronic sensor responsive to at least a portion of a rotatingmagnetic field, said sensor being galvanically separated from a controlsystem or the electric motor of said yarn feeding device andstructurally independent from said yarn feeding device, said sensorbeing positioned at or close to a housing of said yarn feeding device atan exterior mounting location where at least a portion of a magneticfield which rotates with said component within said yarn feeding deviceleaks through said housing and is detectable, said sensor detecting arotational speed of said component based upon detection of said portionof the magnetic field, said portion of said magnetic field beingotherwise unused in said yarn feeding device at said mounting locationof said sensor.
 2. The yarn processing system according to claim 1wherein said sensor generates a speed signal representing the rotationalspeed of said component based upon detection of said portion of saidmagnetic field.
 3. The yarn processing system according to claim 2wherein said sensor has at least one signal exit port connectable tosaid accessory device by a cable and a releasable connector.
 4. The yarnprocessing system according to claim 1 wherein said sensor is connectedfor its power supply to said accessory device, or to a power supply boxof said yarn feeding device, or to its own power supply source.
 5. Theyarn processing system according to claim 1 wherein said accessorydevice is a controlled yarn impregnation device provided along the yarnpath of the yarn.
 6. The yarn processing system according to claim 1wherein said accessory device is a controlled slip conveyor associatedwith the yarn along the yarn path.
 7. The yarn processing systemaccording to claim 6 wherein said controlled slip conveyor is mounted atthe yarn feeding device at its inlet or outlet side.
 8. The yarnprocessing system according to claim 1 wherein said accessory device isa controlled yarn brake associated with the yarn along the yarn path. 9.The yarn processing system according to claim 8 wherein said controlledyarn brake is mounted adjacent at least one of the inlet side and theoutlet side of the yarn feeding device.
 10. The yarn processing systemaccording to claim 1 wherein said accessory device is a drive of arotatably driven storage bobbin carrying yarn which is supplied to saidyarn feeding device.
 11. The yarn processing system according to claim 5wherein said yarn impregnation device is mounted by a carrier to theyarn feeding device and said sensor is secured to said carrier, saidcarrier being mounted to said yarn feeding device and the sensor beingpositioned at the mounting location at or close to an inlet side housingend wall of the yarn feeding device.
 12. The yarn processing systemaccording to claim 11 wherein said yarn impregnation device includes atleast one treatment element and a control unit for an electric motorwhich drives said treatment element, said control unit being permanentlyor releasably connected to a signal exit port of the sensor.
 13. Theyarn processing system according to claim 1 wherein a receiving socketfor said sensor is provided at said mounting location at the housing ofthe yarn feeding device, said receiving socket comprising one of: aninsertion socket; a threaded bore; and a hang-in opening.
 14. The yarnprocessing system according to claim 1 wherein said portion of themagnetic field originates from a driving, a controlling or a monitoringmagnetic field of the electric motor of said yarn feeding device. 15.The yarn processing system according to claim 1 wherein said portion ofthe magnetic field originates from a permanent magnet situated on arotatable winding element of the yarn feeding device, said permanentmagnet being part of a rotation detector integrated into said yarnfeeding device.
 16. An electronic sensor for generating a signalrepresenting the rotational speed of a rotating component of a yarnfeeding device which is driven in a controlled fashion by an electricmotor received within a housing of the yarn feeding device, said sensorbeing galvanically separated from a control system or the electric motorof the yarn feeding device and being mounted at or close to the housingof the yarn feeding device at an exterior mounting location, said sensorcomprising a pick-up head responsive to at least part of a magneticfield rotating with the component within the yarn feeding device andleaking through the housing, the part being unused for the functioningof the yarn feeding device at the mounting location of said sensor. 17.The electronic sensor according to claim 16 wherein said sensorcomprises a probe-shaped housing which receives said pick-up head and afixation device for positioning said sensor at the mounting location,and said sensor housing includes amplification and evaluation circuitry.18. The electronic sensor according to claim 17 wherein said fixationdevice of said sensor housing is defined by at least one body having anadhesive coating for securing said sensor to the housing of the yarnfeeding device, said body being constructed of one of: plastic; rubber;and foam material.
 19. The electronic sensor according to claim 17wherein said fixation device comprises a tensioning band.
 20. Theelectronic sensor according to claim 16 wherein said fixation deviceincludes at least one spring-loaded clamp for fixing the sensor at aprotrusion of the housing or a cooling fin of the housing.